Regulation of SIRT1 determines initial step of endometrial receptivity by controlling E-cadherin expression

Sirtuin 1 (SIRT1), originally found as a class III histone deacetylase, is a principal modulator of pathways downstream of calorie restriction, and the activation of SIRT1 ameliorates glucose homeostasis and insulin sensitivity. We examined the role of SIRT1 in the regulation of uterine receptivity using Ishikawa and RL95-2 endometrial carcinoma cell lines. Exogenous expression of SIRT1 significantly enhanced E-cadherin expression, while small interfering RNA-mediated depletion of endogenous SIRT1 resulted in a significant reduction of E-cadherin expression. A SIRT1 activator resveratrol elevated E-cadherin expression in a dose dependent manner, while SIRT1 repressors nicotinamide and sirtinol exhibited a dose dependent reduction of E-cadherin expression. We also showed that both forced expression of SIRT1 and activation of SIRT1 promote E-cadherin-driven reporter gene constructs, and SIRT1 is localized at E-cadherin promoter containing E-box elements in Ishikawa cells. Using an in vitro model of embryo implantation, we demonstrate that exogenous expression of SIRT1 and stimulation of SIRT1 activity resulted in the Ishikawa cell line becoming receptive to JAR cell spheroid attachment. Furthermore, resveratrol enhanced E-cadherin and Glycodelin protein expression at sites of intercellular contact, suggesting an additive role of resveratrol in promoting implantation. The initial step of human reproduction depends on the capacity of an embryo to attach and implant into the endometrial wall, and these results revealed the novel mechanism that activation and increased expression of SIRT1 play an important role in uterine receptivity.     

Flow-cytometric isolation and enrichment of teleost type A spermatogonia based on light-scattering properties

The transplantation of germ cells is a powerful tool both for studying their development and for reproductive biotechnology. An intraperitoneal germ cell transplantation system was recently developed for use in several teleost species. Donor germ cells transplanted into the peritoneal cavity of hatchlings migrated toward and were incorporated into the recipient's genital ridges, where they underwent gametogenesis. Among male germ cells, only type A spermatogonia were capable of colonizing the recipient gonads, unlike those at more advanced stages. The enrichment of type A spermatogonia is therefore important to achieve efficient donor-cell incorporation and subsequent donor-derived gametogenesis. Here we established a simple and rapid system of isolation and enrichment for fish type A spermatogonia, using flow cytometry. Type A spermatogonia were found to have distinctive forward and side light scatter properties compared to that with other types of testicular cell. Based on these characteristics, we were able to isolate and enrich type A spermatogonia by using flow cytometry. After intraperitoneal transplantation, the enriched type A spermatogonia could be successfully incorporated into the recipient genital ridges. This flow cytometry approach using forward and side light scatter was also found to be applicable to other salmonid and sciaenid species, suggesting that it could be a powerful tool for isolating and enriching transplantable type A spermatogonia in a wide range of teleosts. We expect this method to contribute significantly to germ cell biology and biotechnology.     

A protein domain-based interactome network for C. elegans early embryogenesis

Many protein-protein interactions are mediated through independently folding modular domains. Proteome-wide efforts to model protein-protein interaction or "interactome" networks have largely ignored this modular organization of proteins. We developed an experimental strategy to efficiently identify interaction domains and generated a domain-based interactome network for proteins involved in C. elegans early-embryonic cell divisions. Minimal interacting regions were identified for over 200 proteins, providing important information on their domain organization. Furthermore, our approach increased the sensitivity of the two-hybrid system, resulting in a more complete interactome network. This interactome modeling strategy revealed insights into C. elegans centrosome function and is applicable to other biological processes in this and other organisms.     

The proline-rich protein palladin is a binding partner for profilin

Palladin is an actin-associated protein that has been suggested to play critical roles in establishing cell morphology and maintaining cytoskeletal organization in a wide variety of cell types. Palladin has been shown previously to bind directly to three different actin-binding proteins vasodilator-stimulated phosphoprotein (VASP), alpha-actinin and ezrin, suggesting that it functions as an organizing unit that recruits actin-regulatory proteins to specific subcellular sites. Palladin contains sequences resembling a motif known to bind profilin. Here, we demonstrate that palladin is a binding partner for profilin, interacting with profilin via a poly proline-containing sequence in the amino-terminal half of palladin. Double-label immunofluorescence staining shows that palladin and profilin partially colocalize in actin-rich structures in cultured astrocytes. Our results suggest that palladin may play an important role in recruiting profilin to sites of actin dynamics.     

Environmental risks posed by heavy metal contamination from mine waste: Case study from northwest Iran

Mining activities produce waste tailings that can be a significant source of pollution in the surrounding ecosystem. This study was designed to estimate the magnitude of Fe, As, Pb, Cd, Mn, Ni, Zn, and Cr in soil impacted by activities in the Moeil iron ore mine area of northwestern Iran and initially assess the potential risk to nearby residents and ecological habitats. For this, concentrations of elements in 24 samples from 8 locations were analyzed by inductivity coupled plasma optical emission spectrometry. Concentrations of heavy metals reported for samples collected from the area ranged from 50,247–466,200 mg/kg for Fe, 40–10,827 mg/kg for As, 9–84 mg/kg for Pb, 0.2–58.4 mg/kg for Cd, 32–424 mg/kg for Mn, 4–32 mg/kg for Ni, 37–60 mg/kg for Zn, and 32–337 mg/kg for Cr. Reported levels of Fe and As in particular are indicative of severe contamination and imply a high risk to ecological receptors. Reported levels of arsenic also imply elevated cancer and non-cancer health risks to residents who work in or pass through the area. Reported levels of Cd and Cr in soil samples also indicate an elevated cancer risk posed by these metals. The result of this study indicates it is important to estimate potential contamination of soils and drinking water wills in the vicinity of Moeil village to arsenic and heavy metals.     

Expression of PD‐1/LAG‐3 and cytokine production by CD4+ T cells during infection with Plasmodium parasites

CD4⁺ T cells play critical roles in protection against the blood stage of malarial infection; however, their uncontrolled activation can be harmful to the host. In this study, in which rodent models of Plasmodium parasites were used, the expression of inhibitory receptors on activated CD4⁺ T cells and their cytokine production was compared with their expression in a bacterial and another protozoan infection. CD4⁺ T cells from mice infected with P. yoelii 17XL, P yoelii 17XNL, P. chabaudi, P. vinckei and P. berghei expressed the inhibitory receptors, PD‐1 and LAG‐3, as early as 6 days after infection, whereas those from either Listeria monocytogenes‐ or Leishmania major‐infected mice did not. In response to T‐cell receptor stimulation, CD4⁺ T cells from mice infected with all the pathogens under study produced high concentrations of IFN‐γ. IL‐2 production was reduced in mice infected with Plasmodium species, but not in those infected with Listeria or Leishmania. In vitro blockade of the interaction between PD‐1 and its ligands resulted in increased IFN‐γ production in response to Plasmodium antigens, implying that PD‐1 expressed on activated CD4⁺ T cells actively inhibits T cell immune responses. Studies using Myd88^?/?, Trif^?/? and Irf3^?/? mice showed that induction of these CD4⁺ T cells and their ability to produce cytokines is largely independent of TLR signaling. These studies suggest that expression of the inhibitory receptors PD‐1 and LAG‐3 on CD4⁺ T cells and their reduced IL‐2 production are common characteristic features of Plasmodium infection.

     

Virus Excretion from Foot-And-Mouth Disease Virus Carrier Cattle and Their Potential Role in Causing New Outbreaks

The role of foot-and-mouth disease virus (FMDV) carrier cattle in causing new outbreaks is still a matter of debate and it is important to find out these carrier animals by post-outbreak serosurveillance to declare freedom from FMDV infection. In this study we explore the differences in viral shedding between carrier and non-carrier animals, quantify the transmission rate of FMDV infection from carriers to susceptible animals and identify potential viral determinants of viral persistence. We collected nasal and saliva samples from 32 vaccinated and 7 unvaccinated FMDV carrier cattle and 48 vaccinated and 13 unvaccinated non-carrier cattle (total n=100) during the acute phase of infection (up to 28 days post-challenge) and then from limited number of animals up to a maximum 168 days post-challenge. We demonstrate that unvaccinated cattle excrete significantly higher levels of virus for longer periods compared with vaccinated cattle and this is independent of whether or not they subsequently become carriers. By introducing naïve cattle in to the FMDV carrier population we show the risk of new outbreaks is clearly very low in controlled conditions, although there could still be a potential threat of these carrier animals causing new outbreaks in the field situation. Finally, we compared the complete genome sequences of viruses from carrier cattle with the challenge virus and found no evidence for viral determinants of the carrier state.     

Plasmon-Enhanced Fluorescence Biosensors: a Review

Surfaces of metallic films and metallic nanoparticles can strongly confine electromagnetic field through its coupling to propagating or localized surface plasmons. This interaction is associated with large enhancement of the field intensity and local optical density of states which provides means to increase excitation rate, raise quantum yield, and control far field angular distribution of fluorescence light emitted by organic dyes and quantum dots. Such emitters are commonly used as labels in assays for detection of chemical and biological species. Their interaction with surface plasmons allows amplifying fluorescence signal (brightness) that accompanies molecular binding events by several orders of magnitude. In conjunction with interfacial architectures for the specific capture of target analyte on a metallic surface, plasmon-enhanced fluorescence (PEF) that is also referred to as metal-enhanced fluorescence (MEF) represents an attractive method for shortening detection times and increasing sensitivity of various fluorescence-based analytical technologies. This review provides an introduction to fundamentals of PEF, illustrates current developments in design of metallic nanostructures for efficient fluorescence signal amplification that utilizes propagating and localized surface plasmons, and summarizes current implementations to biosensors for detection of trace amounts of biomarkers, toxins, and pathogens that are relevant to medical diagnostics and food control.